Hydrocarbon conversion



July 18, 1944.

E. F. NELSON HYDROCARBON CONVERSION Filed April 27, 1940 All Patented July 18, 1944 mmaocann coNvEasioN Edwin F. Nelson, Chicago, lll., as'signor to Universal Oil Products Company, Chicago, Ill., a corporation of Delaware Application April 2.7, 1940Serial No. 331,925-

This is a continuation-impart of my co-pending application Serial No. 256,633 `iiled'February 16,1939.

This invention relates to a process for producing gasoline of high octane rating Kby a combination involving thermal cracking of the charge ing oil followed bycatalytic treatment of the clean vaporous hydrocarbons formed in the thermal cracking treatment. IMore specically. the invention provides for passing` the stream of vaporous hydrocarbons from the vaporizing and 4 omini,` (ci. 19e- 49) of temperature and pressure toobtain a gasoline product which is substantially saturated in character. On the other hand, `the thermal cracking system may be operated so as to obtain optimum conversion to lighter hydrocarbon oils amenable to catalytic cracking and the vapors separatedI in the vaporizing and separating chamber commlngled with a relatively lighthydrocarbon oil v introduced from an external source or with nonseparating chamber of the thermal cracking system in contact with a bed of catalytic material capable of promoting conversion thereof into more desirable hydrocarbons or one capable of substantially desulfurizing said stream of vaporn 4 os hydrocarbons.

In my previous application, Serial No. 256,633, I proposed to operate a`thermal cracking system under 'conditions' suitable for obtaining charging oil amenable to catalytic cracking preferably with a minimum production of gasoline.- A further object of the invention was to produce a hydrocarbon oil charging stock for catalytic cracking which was highly unsaturated, because such materials are particularly well suited for cat.

alytic cracking.

In my present invention the thermal cracking system maybe operated to produce either opti" mum yieldsy of gasoline or minimumyields of gasoline. Where optimum yields are formed in the thermal cracking system, the vapors from the vaporizing and separating chamber are preferably subjected to contactlwith the bed of catalytic material at a relatively low temperature so as to obtain desulfurization thereof. In such cases, non-condensible gases formed in the process or, when desired, a hydrocarbon oil intro,- duced from an external source may be commingled with the vapors subjected to treatment to supply hydrogen to form hydrogen sulfide i'rom the sulfur which presumably exists as mercaptans, free sulfur, or as sulfur addition products in said vapors;

In another manner of operating the process y -of the invention, the thermal cracking system ymay be operated to produce optimum yields of gasoline and the resulting vapors separated in the vaporizing and separating chamber commingled with a relatively light hydrocarbon oil introduced from an external source and/or with noncond-ensible gases formed in the process, the mixture being subjected to' contact with the bed of catalytic material under selected conditions of temperature and pressure so as to obtain a gasoline product which is substantially saturated v and having a relatively high octane rating.

The invention, however, is lnot limited to the use of the light hydrocarbon oil introduced from an external source or to the method which involves the recirculation of the non-condensible gases formed in the process but may employ, for example instead, a relatively light o'il separated from the intermediate conversion products or, on the other hand, the relatively clean vapors from the thermal cracking treatment may be subjected to treatment in contact withthe vbed of catalytic material without the addition of any extraneous material.

In one embodiment-ther invention may comprise subjecting a relatively heavy oil `to thermal cracking treatment in a heatingcoil and vcommunicating reaction chamber under conditions regulated to effect optimum conversion 'to gasoline, separating clean vaporous conversion products from non-vaporous liquid residue and recovering the latter, commingling said clean `vaporous, conversionl products with uncondensi- 'ble gases formed in the process and subjecting A hydrocarbonscontained in said vapors, fraccondensible gases formed in the process and the.

resulting mixture passed in contact with the bed ot catalytic material under selected conditions tionating the resulting conversion products to substantially separate fractionated vapors boiling in the range of gasoline from the higher boiling intermediate conversion products andcondensing the latter as redux condensate, commingling said reiiux condensatey with the charging oil and l supplying the mixture to said thermal cracking c treatment as said relatively heavy hydrocarbon oilcooling and condensing said fractionated vapors, separating the resulting distillate and gas. recovering the. former,- and commingling a -portion ot -said gas as the uncondensible gases y with said 'relatively clean vaporous conversion products.

trates diagrammatically in ,conventional side elevation one specific form of the apparatus which may be used to accomplish the objects of the invention and 'embodying the principal features above referred to.

Figures 2 and 2A are illustrations of the fourway inlet and outlet valves VI and V2 diagrammatically indicated in Figure 1. Figure 2 shows the valves in one position while Figure 2A shows the passageways therethrough shifted.

Referring to Figure 1, the reference numeral 1 indicates a heating coil disposed within furnace 2 by means of which the required heat is supplied to the oil introduced in the manner to be described later to bring it to the desired cracking temperature, preferably ata substantially superatmospheric pressure. The temperature and time-of contact of the oil in heating coil I may be varied over a relatively wide range depending upon the results desired. When optimum conversion into gasoline boiling range hydrcarbons is desired, temperatures within the range of 850 to 1050 F., or more may be employed with a superatmospheric pressure ranging, for example, from 200 to 800 pounds per square inch. n the other hand, when optimum conversion to light oil is desired with aminimum production of gasoline, temperatures may range from 800 to 1100 F., with a superatmospheric pressure of from 100 v to 800 pounds or more per square inch,

In any event,.the conversion products from heatingcoil I are directed through line 3 and valve 4 to reaction chamber l which is preferably operated at a superatmospheric pressure substantially equal to or slightly less than that employed on the outlet ofl heating coil I and wherein appreciable continuous cracking of the conversionV pass through substantially the entire length ofv the reaction chamber and are directed in commingled state from the lower portion of this zone through line 6 and valve 1 to vaporizlng and separating chamber 8. Chamber 8 is maintained at a substantially reduced pressure relative to that in chamber I which may range, for example, from 50 to 200 pounds or more per square inchby the erated catalytic reactors and provision is therefore made, in the case here illustrated, for increasing the temperature to the desired degree .prior to their introduction to the catalytic reactors by directing the clean vaporous hydrocarbons in line II through line 22 and valve 2l into heating coil I8 are directed through line 2l and valve 2| back to line II by means of which they lare supplied to valve VI.

for the purposeof supplying hydrogen to the reactants. Theprobable reaction involvediin the formercase being one of hydrogen transfer from the more saturated hydrocarbons to the unsaturated hydrocarbons while the reaction in the latter case probably involves the dehydrogenation of the more saturated molecules, the hydrogen thus evolved being used for producing by,

drogen sulfide from the sulfur contained in the sulfur bearing material subjected to conversion. 'I'he light hydrocarbon loil `introduced from an exterior source for this purpose may comprise, for example, a relatively light gas oil, naphtha.

"or kerosene whichis supplied by way of linehll and valve Il to pump I5 which discharges through line I6 and valve II into heating coil I8. When an oil from an exterior source is used for the purpose of supplying hydrogen during the desulfurisation treatment, preferably only uushydroearregulation .of valve I in line I and the reduction in pressure between these two sones is suiiicient to eifect substantial further vaporization of the4 liquid conversion products supplied to chamber l whereby said liquid conversion products are reduced to a non-vaporous residue of the desired characteristics. Separation of the clean vaporous hydrocarbons and non-vaporous residue is accomplished in chamber l and provision is made for removing the residual liquid from the lower portion of this-none through line l and valve Il tvcoolinsandstoraseorelsewnereasdesired.

A to valve 'VI after' which they are supplied to alf ternately operated catalytic reactors for further treatment in the manner tobe' describedmore fully later.` Ordinarily. however, cleanvaporous hydrocarbons separated-within chamber! are belowthetemperaturerequiredtoeifecttheirdesired catalytic conversionin the alternateiyop- (u bon oil is heated in heating coil I8 and the resulting heated oil commingled with the vapors in line II to form amixture having a temperature ranging. i'orexample. from 400 Vto 800'1'2, the

mixture thereafter being 'subjected to treatment in the manner to .be described later.

In another manner of.A operation, only the oil introduced fromr an exterior source is subjected toheating in coil Il, after which it is commingled with the clean vapors In line II to form a mixture having a temperature ranging. for example, from 800 to 850 C., which is thereafter subjected to treatment in the alternately 0961'- ated catalytic reactors so as toJQrm a'gasgline product which is substantially saturated in char. acter.

Another method of operation may involve commingling uncondensed normally gaseous hydrocarbons formed in the process or light intermediate conversion products with or without additional heating with 'the vaporous conversion products in line I I, the latter having been heated to a higher' temperature in heating coil I8 or with no additional heating and with or without the addition of the light oil introduced from an outside source, all of which will be described more fully later,-

YIn any event, the hydrocarbon reactants supplied to valve VI are alternately subjected to contact with tl'I/egcatalytic material in reactors A and B. while the catalytic material in reactors A and B is alternately subjected to reactivation. the case hereillustrated, switching of stream of reactants land reactivating gases from one reactor to the other is accomplished by means of valve Vl, while switching of the spent reactivating gases and conversion products is accomplished b`y means of valve V2. In order to simplify the description without unnecessary complications, each of the switching valves is illustrated as a four-way valve which may be adjusted to either of the positions illustratedin Figures 2 and 2A. When reactor A is on process and the catalytic material in reactor B is undergoing reactivation, valve Vl is adjusted tothe position illustrated in Figure 2 and valve V2 is adjusted to the position illustrated in Figure 2A, and when reactor B is on process and 'the catalytic material in reactor A is undergoing reactivation, valve VI is adjusted to the position illustrated in Figure 2A and valve V2 to tion illustrated in Figure 2.

When reactor A is on process, reactants supplied to valve V-I pass therethrough into line 24 by means of which they are supplied to reactor A, passing therethrough in contact with' the catalytic material disposed therein and the conversion products from reactor A pass through line 25 and valve 25 for treatment inthe manner to be described. When reactor B is on process, reactants supplied to valve Vl pass therethrough the posiinto line 21 by means of which they are supplied to reactor B and the conversion products from reactor B are directed through lin'e 28 and pass through valve V2 into line 28 for treatment in the manner to be described. i

When the catalytic material in reactor B is undergoing reactivation,` reactivating gases comprising, for example, combustion gases containing controlled minor amounts of oxygen'heated to aV temperature ranging from 800 to 1100 F., are supplied tothe system by way of line 29, passing through'valve VI into line 21 by means of which they are supplied to reactor B. The

carbonaceous materials deposited upon the catalyst during a prior processing period are burned when the reactivating gases are brought in contact therewith and the resulting spent reactivating gases and combustion products are removed from reactor B by way of line 28, passing through valve V2 into line 30, after which they heat therefrom or, when desired, regulated portions may be recirculated after readjusting the oxygen cqicentration and temperature thereof as the fresh reactivating gases. When the catalytic elements are disposed' for the purpose of supplying or withdrawing heat from the bed of employed within I may be disposed of preferably after recovering material in reactor A is undergoingereactivation, 4 l

fresh reactivating gases iri'lin'e 29 pass through valve VI into line 2l by means of which they are supplied to reactor A and spent reactivatinggases and conversion lproducts from reactor A pass through line 2,5 and valve V2 into line lli for'v treatment as previously described.

Reactors A and B, in the case here illustrated, may comprise, for example, suitably insulated chambers containing one or a plurality of beds of the catalytic material wherein the conversion reaction is carried out under substantially adiabatic conditions. When desired. however. other types of reactors well known in the art, may be employed, such as, for example, those which contain a plurality of tubular elements containing the catalytic material and wherein a suitable heat convective medium may be circulated yin contact with said tubular elements to supply or vwithdraw heat therefrom or, on the other hand, reactors A and B may contain avbed of catalytic material in which suitable tubular said catalytic material. i In view of the above, it is obvious that it is not the intention to limit the invention `ty 'emi ploylng any specific type of reactor, the invention being limited only with respect to the result. to be accomplished. l l

` Catalysts which have been found to be effective in the catalytic cracking and krlesulfuriiation. treatment of hydrocarbon vapors may comprise pellets or granules of silica or other slliceous and refractory materials composited with compounds selected from the group consisting of alumina,

zirconia, vanadia, and thoria. I-nladdition, the y hydrosilicates of alumina, acid treated clays, or the like. have also been found to lbe effective in the treatment above referred to. Although the catalysts above recited are generally considered to Vbe the preferred catalysts, their use is not to b'e construed as a limiting feature, for various other catalysts well known to those in the art may be the broad scope of the invention. 1 t

The conversion temperatures employed in the catalyticltreatment, whether it is desired to obtain desulfurization, hydrogen transfer/to obtain a substantially saturated gasoline, or catalytic cracking, will fall kwithin the-range -of 590 to -1200 F. Preferably, however, .for desulfurization temperatures of the order of 400 to 600 F., are employed for low temperature treatment, for hydrogen transfer temperatures within the range of 600 to 850 F. are employed, andvfor high temperature catalytic cracking temperatures within the range of 800 to 1200l F., are ernployed with a pressure. in any case, ranging. for example, from substantially atmospheric to 200 pounds or more per square inch..

The conversion products in line 28 are sup,

plied to fractionator 3| wherein fractionated vapors boiling substantially in the range of. gasoline are substantially separatedi'rom the higher boiling conversion products. In the case here i1- lustrated, fractionator Il is preferably operated at approximately the' same pressure as that employed on the outlet of thecatalytic=reactors. The heavy conversion products `separated from the lightv fractionated-vapors in fractionator 8| are condensed therein as reflux condensatel and, when desired, a light fraction may'be separated therefrom comprising essentially a hydrocarbon oil boiling substantially in the range of 'a light gas oil, kerosene or naphtha. Heavy reflui condensate separated in fractionator .3| is removed therefrom by way of line!! and directed through valve 3l to pump 34. Pump -)l'c iischargesthrough line 3B and, when desired. the heavy reflux condensate may be'recovered as a product of the process by way of line and valve Il,- in which n case onlythe hydrocarbon oilv charging stock suppliedA in the manner to bev described latergfis sub- Jected to treatment in the manner previously de- Iscribed. Preferably, however, the redux condensate in line ll is directed through valve Il into heating coil |.for treatment,as previously defractionator JI through line 3l and is directed through valve Il to pump 4I. Pump 4l discharges through line 42 and this fraction is preferably directed through valve Il into liney i6 by means .or

which it is supplied to heating coil IB wherein it is heated to the desired conversion temperature and thereafter commingled with the relatively cleanv vaporous conversion products in line Il. Since the light fraction removed from fractionator 5I as above described is a relatively refractory oil, when such oil is used it may be heated to a relatively high temperature in heating coil I5 so that D011 mixing with the clean vaporous lhydrocarbons in line il the desired conversion temperature is obtained prior to the introduction of the mixture to the catalytic reactors, or, when desired, the light oil fraction and the clean vaporous hydrocarbons may both be supplied to heating coill5 and heated to the desired conversion temperature. In some cases, however, heating of the light fraction from fractionator 5l may not b e necessary and in such cases the light oil in line 52 may be directed through'line' and valve Il into linel il, commingling therein with-thel materials to be oonverted in the catalytic reactors.

Charging oil for the process which may comprise a relatively heavy hydrocarbon oil, such as topped or reduced crude oil or, when desired,

- crude oil or any desired fraction thereof; is supplied to the system by way of line 55 and is directed through valve 41 to pump 45. Pump 45 discharges through line 55 and-'when the charging oil contains light hydrocarbons which may boil within the range of the fractionated vapors or within the range of the light hydrocarbon oil, it

may be directed through line 55 into fractionator 5i and fractionated therein with the conversion products supplied as previously described. On the other hand, when the charging oil contains only heavy hydrocarbons and particularly in the case where it is desired to recover the heavy rein with the relatively clean vaporous hydrocarbons for treatment in the manner previously described.

In some "cases, however, since these gases are at I a relatively low temperature, it may be desirable to supply heat thereto prior to commingling the same with the vapro'us hydrocarbons in line Il, and this may be accomplished by directing them through line 68 and valve 59 into line I5 by means of which they are supplied either alone or in commingled state with either the vaporous hydrocarbons from line II and/or with the light oil introduced from an external source and/or with the light oil from fractionator 5| to heating coil I5, and after4 receiving heat therein subsequently returned to lln'e il.

Examples of one specific operation of the process as it may be accomplished in an apparatus such as illustrated and above described is approximately as follows:

4Example I Heavy reflux condensate formed as hereinafter described is subjected to conversion at a temperaturev of 920 F., -and at a superatmospheric pressure of 200 pounds per square inch in a heating coil and communicating reaction chamber. The conversion products are supplied to a 4vaporizlng and separating chamber operated at a superatseparated in the manner abovementioned are commingled with a portion of the uncondensed normally gaseous products separated as hereinafter described and the mixture alternately supment in one reactor the catatlytlc material condensed gases from condenser 55, is directed through line 55 and valve 51 into receiver 55 wherein the distillate and gases are collected and separated. A portion of the distillate collected and separated in'receiver 55 may be returned to the upper portion of fractionator 3| by well known means, not shown, as a refluxing and cooling medium therein, while the remaining portion of the distillate in receiver is removed therefrom by way of line 55 and valve 55 and recovered as a product of the process or subjected to any desired further treatment.

Undissolved and uncondensed gases collected and separated in receiver 55 are removed therefrom by way of line 5I and may be directed through line 52 .and valve 55 and recovered as a product of the process. However, since these gases contain ordinarily a relatively high proportion of hydrogen and methane whereby they are particularly adaptable for use in the desulfurizatlontreatment of the relatively clean vaporous hydrocarbons or whereby they may be employed -ior producing a substantially saturated gasoline from said relatively cleanyaporous hydrocarbons, at least a` portion thereof is preferably directed through v valve 55 to compressor. Compressor 55 discharges through line 55 and all or a portained in the other reactor is subjected to reactivation by passing a stream oi oxygen-containing reactivating gases in contact therewith at a temperatureof approximately 920 F., to remove by combustion the carbonaceous materials deposited during the prior catalytic treatment of the above mentioned mixture. t

The conversion products leaving the catalytic -reactor are subjected to fractionation in com- The fractionated vapors are subjected to cooling and condensation and the resulting distillate and gas collected and separated. The distillate is recovered as a product of the process and a portion of the gases remaining uncondensed and undissolved inthe distillate is commingled withl the clean vaporous hydrocarbons from the vaporizing and separating chamber as above described.

When employing the conditions above mentioned, approximately 50% of 80 octane number gasoline with a sulfur content below 0.02% and approximately 40% by volume of liquid residue Y may be obtained as' products of the process.. the

balance being attributed principally. to gas and loss.

Example I! Heavy reflux condensate formed as hereinafter described is subjected to conversion at a temperature of 920 F., and at a superatmospheric pressure of 200 pounds per square inch 'in a heating coil and communicating reaction chamber. The conversion products are supplied to a vaporizing and separating cham-ber operated at a superatmospheric pressure of 75 pounds per square inch wherein relatively clean vaporous hydrocarbons are substantially separated from non-vaporous residue and the latter recovered as a product oi the processB The relatively clean vaporous hydrocarbons from the vaporizing and separating chamber are oommingled with a 36 A., P51. gravityfgas oil fractionuheated and vaporized in an external heating coil at a temperature of 950 F., and the mixture at a temperature oi @GW ilk, is alternately supplied to one 'oi two reaction zones containing a silica alumina catalyst. Simultaneously with the catalytic treatment in one reaction zone, the cat alytic material contained in the other reactor is subjected to reactivation by passing s. `stream o! oxygelu-containingl reactivating gases in contact therewith at a temperature ci approximately 92 R, to remove ley combustion the carlconaceous materials deposited during the prior treatment of the above mentioned The conversion products leaving mixllul'eo mingled state with the charging y oil, the latter comprising essentially a 24 A. P.

I. gravity Mid Continent reduced crude oil and fractionated vatreatment in the manner above described.

catalytic n the catalytic- 'resctor are subjected to fractionation in comiractions being con' densed asmreux condensate and subjected to loil vmay be obtained. the balance beins attributed principally. to gas and loss.

I claim as my invention: i, l.. A process for the conversion of, hydrocarbon whichcomprises subjecting a charging oil to thermal cracking, separating the resultant cracked products into vapors and residue7 subjeetins substantially all of Ithe vapors tothe action of a Acracking catalyst in the presence oi iiydrocarbon oli, derived from a source independent ofthe vapors and capable oi transferring hydrogen to said vapors, 600 to about 850 F., for a timeperioc suitable for producing a substantially oieinndreelsosoline.

The process of claim i `further characterised in that the cracking catalyst comp silica and process oi claim 1 further characterized in that heat is supplied to said vapors before ccn-l tacting the latter with thel crac'catalyst.v

4, A process for the conversion of hydrocarbon oil which comprises subjecting a charging oil to al cracking. separating the resultant cracked `products into vapors and residue. sub

jectins substantially all ci the vapors to the action s of a crac catalyst in the pee ci s hydrocarbon oil, derived -irom a source independent of the vapors and *capablel ci' transfer hydrogen to said vapors, for a time period and at a temperature in excess of 600 Il', suitable for producing a substantially olen-iiree gasoline.

nnwm n above menet a temperature ci from about n 

